Sitting in a teepee in the peaceful Kent countryside, surrounded by campaigners from across the UK mulling over the future of renewable energy and swapping vegan cake recipes, you could be forgiven for temporarily forgetting the outside world and its many woes. Perhaps, then, we must also forgive the police at the climate camp in Kingsnorth this week for losing their grip on reality, as the sense of perspective which should have underpinned their policing strategy for the event flew straight out of the canvas window. The police – primarily from the local Medway force but Metropolitan officers are also in evidence – have raided the camp twice now, confiscating items that included crayons, disabled access ramps, marker pens, banners, radios for relaying fire and medical emergency information, the nuts and bolts holding toilet cubicles together and blackboard paint. They have found it necessary to use pepper spray without provocation, and several campers have been arrested and bailed off the site for "obstructing" increasingly aggressive police officers. Everyone who enters the site is being searched. Police officers are taking anything away that "could be used for illegal activity", with efforts being made to strip protesters of such hardcore weapons of choice as bits of carpet, biodegradable soap and toilet paper. In the absence of any serious threat, the police clearly found it necessary to justify their presence with an unprovoked attack on personal hygiene. When I met with Medway police ahead of climate camp, I asked if officers could be given specific information about the ethos behind climate camp and guidelines on proportional responses. I had hoped that the guidelines would be based on sensible use of discretion and grounds of precedent. I am therefore horrified that police here have used pepper spray, riot gear, physical intimidation, and indulged in bizarre confiscations. It almost feels like an attempt to inflame tensions and provoke protesters into less peaceful behaviour. I was delighted to be invited to take part in climate camp this year; indeed, where better to highlight the government's failure to provide leadership on climate change and environmental degradation than Kingsnorth, the proposed location for the first coal-fired power station in Britain for 30 years. The climate camp protest is a peaceful and legitimate demonstration against a proposed facility that many view as a potent symbol of the government's misguided commitment to highly polluting and unsustainable fossil fuels. Activists from far and wide have travelled to register their disgust at government support for new coal-fired power stations and at the lack of urgent action on climate change. The owner of the land agrees with the camp's activities and the organisers are by now seasoned experts at creating autonomous political spaces in which discussion can flourish. So, as climate campers hold workshops and debate some of the key issues of our time – peak oil, economic downturn, food shortages – scores of police sweat in their riot gear on the other side of the fence. They all clutch a copy of a pocket booklet entitled Policing Protests produced by the ominously titled National Extremism Tactical Coordination Unit, which appears designed to provide endless ways of shutting down legitimate protests. One such tactic has been to smash the windows of vehicles parked outside the camp and to try to tow away cars under the Abandoned Vehicles Act. If only the police were as interested in addressing corporate crimes against the environment as they are in roughing up peaceful protesters. A new coal facility in Kingsnorth would emit up to 8m tonnes of CO2 into the atmosphere each year – and potentially keep doing so for 50 years. That annual emissions figure is as much C02 as the world's 24 lowest emitting countries combined. So any government which commits to more coal-fired power stations – and Kingsnorth is only the first – then claims to be aiming for a massive reduction in carbon emissions by 2020 is living in a fantasy land. The government should be showing real leadership in this debate, with measures to tackle rising energy costs and fuel poverty such as a windfall tax on massive energy company profits, as well as urgently initiating major investment in energy efficiency, renewables, decentralised energy and demand reduction schemes. According to its own figures, we could achieve a 30% reduction in energy use in the UK through existing efficiency technologies alone. Instead, ministers stick with their business-as-usual approach, further enabling the fossil fuel industry to profit and pollute, while paying scant regard to the average citizen or the environment. It is to be commended then, that thousands of citizens have been prepared to travel to Kingsnorth climate camp to demand a say in their country's energy policy and to take action to protect the environment for future generations. I am shocked by the violent and excessive attack on civil liberties meted out by the police here, as is my Green colleague on the London assembly and member of the Metrolitan Police Authority, Jenny Jones, who has already raised concerns with Met commissioner, Sir Ian Blair, and New Scotland Yard. We will be calling for any Met officers who have acted inappropriately to be reprimanded, fined or even sacked. It is crucial that we defend the right to peaceful protest, a right that is under threat from the government's disproportionate anti-terrorism legislation and anti-democratic amendments to its planning bill.